3 Answers
3

Constructing a ship in one of your systems that contains any of the following:

Lasers

Missiles

Kinetic weapons

Things that I haven't verified (but that definitely look like weapons to me):

(Note that fighters, bombers, and bombs were added to the game after the achievement; whether they prevent the achievement or not will depend on how they were programmed.)

Constructing a ship in one of your systems that contains any of the following:

Fighters

Bombers

Bombs and siege modules (And how could you even use one of these? There are going to be some defending fleets that need to be shot before you can use them, and weapons are right out. I suppose you could swoop in at an opportune moment to bomb/siege the system, but then you're going to be at war and have no warships.)

The sub-question: how to best earn the Way of Harmony achievement?

The easiest way to earn this badge is to play with non-aggressive opponents (like, say, Amoebas), and without pirates. As such, you won't have any reasons to build ships with weapons. I cannot imagine earning this badge if pirates or warmonger opponents exist in your game; relying on defense ships you find will not be sufficient to defend you from either pirates or warmongers.

I got the achievement while using Fighters and Bombers. It's still pretty difficult but it works. Since you're pretty limited with special modules they won't do much damage in battles even if specialized for it, and most battle actions are pretty useless with them. But at least you can defend yourself.

Easest way is the play a one opponent and easest diffyculty and oppenents amoeba or automatons. Dont push too much your system to opponent system, because your diblomats go hatred and then they became you in a war.